This invention relates to electronic equipment frames and enclosures, and more particularly to those that can better withstand side-to-side vibration forces so as to be better resistant to damage due to earthquakes, explosions, and other tremor-related activity.
There is an ever-increasing demand for higher force tolerance to earthquakes and other tremors for electronic equipment frames and enclosures (i.e. cabinets). See the Background of the Invention section in U.S. Pat. No. 6,293,637, issued Sep. 25, 2001, entitled xe2x80x9cEarthquake-Resistant Electronic Equipment Framexe2x80x9d, owned by the same assignee of the present invention, and which section is incorporated herein by reference. That patent teaches an improved side support channel for such frames as formed of a specific corrugated shape. There is also U.S. Pat. No. 5,979,672, entitled xe2x80x9cEarthquake-Resistant Electronic Equipment Frame,xe2x80x9d where the disclosed electronic equipment enclosure utilizes a unitized or monocoque-type enclosure formed of one continuous corrugated panel.
Note also U.S. Pat. No. 5,639,150, entitled Electronic Component Enclosure and Method, as also assigned to the assignee of the present invention, where the equipment frame utilizes a side support channel which had a chamfered corner profile. In that particular unit""s frame, the top and bottom panels were formed as separate bolt-on units, i.e. members not integrally connected to the overall equipment frame. Further, the unit required the presence of additional front door, rear door, and side panels to allow the unit to achieve the overall strength that that particular enclosure had been designed to withstand, i.e. it required extra components to be able to pass the so-called Seismic 4 testing criteria.
Another known shape for a corner member of an electronic equipment frame, and particularly one with corner support members having a V-tapered type corrugated profile, is U.S. Pat. No. 4,899,892.
However, notwithstanding all the above prior equipment frame designs, none permit the frame""s overall center of mass (e.g. of the combination of equipment shelves, the electronic equipment itself, and related wiring) to be at a sufficiently high location as currently desired by end-users of such frames. Moreover, none of the above prior art units achieve the needed overall permitted weight for a given frame, while still passing the required Seismic 4 testing, all to address the ever-increasing industry need for such increased weight limits.
The present invention comprises an earthquake-resistant electronic equipment frame made with four corner support channels, each support channel having a generally corrugated profile, including a deep center V-grooved channel, a chamfered outer corner, and deep end flanges with returned lip portions, permitting increased resistance against side-to-side forces. Each side support channel is preferably formed of heavy gauge, i.e. preferably 11 gauge, cold-rolled steel. A series of so-called xe2x80x9cUnistrutxe2x80x9d (Trademark) cross strut members, which combine with the main corner support channels to make an integral frame member, are used to provide extra strength. Further, the respective top and bottom panel assemblies are integrally connected by welding to the respective main corner support channels so that each top and bottom assembly becomes an integral unit with the overall frame. Further, the front and rear top corner edges of the top panel assembly are chamfered, similar to the outer chamfered corner edges of the four main corner support channels, to provide yet further side-to-side resistance to vibration forces.
In an alternate embodiment, additional structure in the form of xe2x80x9cXxe2x80x9d-bracing, i.e. cross bracing, is utilized across the rear opening of the present equipment frame to provide yet additional side-to-side vibration force resistance.
In testing, it has been shown that a equipment frame made in accordance with the present invention will achieve much higher Seismic 4 test results than even those available with the frame made in accordance with the invention of U.S. Pat. No. 6,293,637, or with any other known equipment frame, for that matter. Importantly, such higher test results are achieved without the addition of side panels or doors to the present equipment frame. Also, the center of the overall increased weight achievable with the present equipment frame can be located at up to approximately 65 percent of the overall height of the present frame. That is a height much higher than achievable with any of the known prior equipment frames.